Identification of Borrelia burgdorferi and B. hermsii using DNA hybridization probes

Fragments of plasmid DNA from Borrelia burgdorferi and B. hermsii were cloned and tested for specificity as hybridization probes to identify these two species of pathogenic spirochetes. Three fragments from the 49-kilobase-pair linear plasmid of B. burgdorferi were tested: a 500-base-pair (bp) HindIII fragment (probe 49A), a 445-bp PstI-HindIII fragment (probe 3G), and a 320-bp HindIII fragment (probe 16H). When hybridized to purified DNA or whole spirochetes, all of the probes distinguished B. burgdorferi from the other species examined, including B. hermsii, B. parkeri, B. turicatae, B. coriaceae, B. crocidurae, and B. anserina. Probe 49A was the most useful, however, hybridizing with all strains of B. burgdorferi originating from both North America and Europe while not cross-hybridizing with B. hermsii. A 790-bp HindIII fragment of B. hermsii DNA hybridized with DNA and whole spirochetes of this species and also with B. parkeri, confirming the close relatedness of these two species. These probes provide a new method of identifying these Borrelia species once the organisms have been grown in culture.